A vertical bearing device that supports a rotating shaft member of a rotary machine such as a large generator and electric motor is publicly known. The vertical bearing device supports both of thrust load in the axial direction and radial load in the radial direction, of the rotating shaft member that extends vertically in the direction of gravitational force. Bearing parts corresponding to axial and radial load of the vertical bearing device become heated by rotation of the rotating shaft member, and therefore need to be appropriately cooled. Conventionally, a vertical bearing device has been adopting an air cooler that cools the whole device mainly by air-blowing, or an oil cooler that cools lubricating oil on the outside. When an air cooler is used, a fan that rotates with the rotating shaft member is used to cool the bearing device by an air flow generated by the fan (Japanese Patent Laid-Open No. 2003-293977). Instead, when an oil cooler is used, a pump device or the like for circulating lubricating oil is used to discharge lubricating oil that lubricates the bearing part to the outside, for example, and the lubricating oil is circulated between the bearing device and the cooler to thereby cool the bearing device (Japanese Patent Laid-Open No. 5-106636).
However, since rotary machines to which the vertical bearing device is applied are becoming larger and high-speed, the heat generated at the bearing parts also tends to increase. For this reason, the vertical bearing device is required to have higher cooling capacity. However, when an air cooler such as that described in Japanese Patent Laid-Open No. 2003-293977 is used, cooling capacity depends on air flow and the contact area between the air flow and radiator fins that come into contact therewith. In other words, to enhance cooling capacity, it is essential to enlarge the surface area of the radiator fins. Accordingly, improvement in cooling capacity causes a problem of enlargement of radiator fins, and therefore enlargement of the vertical bearing device itself.
When an oil cooler is used, enlargement of the vertical bearing device itself can be avoided, but piping from the vertical bearing device to the external oil cooler is required. This complicates structure and maintenance. Moreover, if a failure occurs in the function of the oil cooler or the piping, it becomes difficult to cool the vertical bearing device itself.
Hence, an objective of the present invention is to provide a vertical bearing device that has high cooling capacity, while preventing enlargement and complication of structure and maintenance.